Long ago a friend who owned a tire shop gave me the same advice. New
tires always go in the rear. Regardless of whether the vehicle was
rear or front driven, new tires go on the rear. Better grip in the
rear means better chance that the ass end won't come around, throwing
you into a spin.
Given the foul mood on the list, I feel I must interject that I'm not
asking anyone out to a duel, just saying this caught my attention and
I had never seen this rule challenged.
Just a little poking around turned this up, and much more :

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=52

Gracias,
                    Miguel